Storing energy generated from sunlight, solar batteries are a rapidly growing technology accelerating access to clean, sustainable, cost-effective, and independent electricity worldwide.
Whether you are just doing some initial research or are ready to find the perfect renewable energy storage solution for your property, this guide walks through all the basics you need to know about solar batteries.
What are solar batteries?
Solar batteries provide a solution for storing excess energy generated by photovoltaic (PV) solar panels and play a pivotal role in promoting energy independence. To fully understand how solar batteries work, here is a look at their functionality in two distinct installation scenarios: off- and on-grid.
How Grid-Tied Solar Batteries Work
At home, when your solar panels produce more electricity than your property needs, the excess energy can be transmitted to the power grid or stored in a solar battery. In 2023, 13% of residential solar installations included battery storage, a percentage that has tripled since 2018 and is expected to double once more by 2028.
When operating a smart solar storage system like an Enphase IQ battery, you can control how and when your property is powered by the clean electricity produced on-site. After capturing excess solar power generation throughout the day, backup batteries can then help run appliances, EV chargers, and other devices with stored power overnight, when grid electricity rates are at their highest, or during local power outages.
How Off-Grid Solar Batteries Work
To capture all the electricity produced by a set of solar panels, backup batteries are essential in every off-grid solar energy system’s operation. Whenever new solar power cannot be generated on cloudy days, under snow, or at night, energy stored in a battery can ensure a continuous supply of electricity on-site.
By “off-grid,” we are referring to any solar installation that is not connected to utility power lines. As such, off-grid solar battery storage comes in many forms, from small devices like solar yard lights to portable energy systems and PV installations on remote properties.
Benefits of Using a Solar Battery
Solar battery benefits can be broken down into three main categories: independence, control, and savings.
Backup
From distant, off-grid properties to mobile applications and full-home systems, solar batteries can foster energy independence anywhere. At home, this is critical during local electrical outages, as grid-tied solar panels with batteries can essentially create a self-sustaining, emission-free renewable energy system.
Self-consumption
Without a battery, all the excess solar electricity produced by your panels is sent to the grid, with savings delivered on utility energy bills. By adding battery storage, you can gain greater control over where and when your solar power is consumed. Then with greater control, you can minimize your grid energy imports to limit your carbon footprint and ongoing electricity expenses.
Bill optimization
In the right circumstances, solar batteries can lead to further cost savings on energy expenses against utility bills avoided. Particularly, new net billing structures like Net Energy Metering 3.0 (NEM 3.0) incentivize homeowners to consume more of their own solar energy with battery storage installed on-site.
Solar battery types
There is a massive range of solar batteries available for sale today, each with its own intended purpose, advantages, drawbacks, and cost implications. When looking at residential and commercial energy systems, most solar installations utilize electrochemical storage batteries for backup power, with either lithium-ion or lead-acid chemistry.
Lithium-ion solar battery storage
Similar to that used in electric vehicles and laptops, lithium-ion battery storage is the most common solar battery cell technology installed today. Within the range of lithium-ion batteries, there are several different chemistries on the market. However, for maximum safety and performance, Enphase batteries utilize Lithium iron phosphate (LFP) technology.
Lead-acid and other solar batteries
Beyond lithium-ion, some solar batteries are powered by lead-acid chemistries, a technology that more closely resembles automobile batteries. Lead acid batteries are generally cheaper than lithium alternatives, but rarely last as long or perform as efficiently. While some lead-acid products like Absorbent Glass Mat (AGM) batteries can be a suitable solution for small-scale systems, lithium-ion storage is generally the chemistry of choice among today’s home and commercial property owners going solar.
What to consider when choosing a solar battery
When on the hunt for the perfect solar battery, there are a few key factors to keep in mind beyond chemistry alone, including capacity, lifespan, and cost.
Energy storage capacity
A solar battery’s rated capacity measures how much energy it can store, usually expressed in kilowatt-hours (kWh) or amp hours (Ah). To calculate the amount of storage capacity you should install, you will first need to establish your energy goals, as in, how much of your property you would like to be run with stored solar power.
If you are going completely off the grid (or as much as that is possible in your neighborhood), large amounts of battery storage will be necessary to keep your electricity as green and cheap as possible. On the other hand, if you are primarily interested in battery storage as a solar backup during local electric outages from hurricanes and other extreme weather events, a smaller reserve may be enough to run your home’s essentials.
Whatever your goals, Enphase IQ batteries are easily “expandable,” which means that you can customize your total backup capacity and even add extra storage later in the lifetime of your system.
Cost and expected lifespan
Although cost and expected lifespan are separate buying factors, they are both pieces of the same puzzle: value. When considering the value of your solar battery, you must look at how its upfront cost compares to its performance over time.
Upfront, home solar storage usually costs between $5,000 and $10,000 for each battery, including expenses for hardware and installation. While costs vary depending on product type, capacity, and elected brand, adding multiple batteries to a full-home system can also increase total storage costs up to $20,000.
In most cases, the expected lifespan of a solar battery is expressed in a “cycle count,” which refers to the number of complete charges and discharges the system can handle before its capacity falls below a certain level. Expected solar battery lifespan can also be determined by the manufacturer’s warranty period and the company's longevity to serve the warranty.
Therefore, when evaluating solar battery choices with similar performance and costs, a product with more expected lifecycles may be a better value. As a long-term investment in your property’s energy costs, it is also important to consider the warranty of a solar battery before making your final design and purchasing decisions.
Final Thoughts and Solar Storage FAQ
Remember, choosing the right solar battery isn't just about finding the most powerful or the cheapest option, it's about finding a solution that fits your unique energy needs. Before purchasing your battery or batteries, be sure to talk to a solar expert about what may be best for your home, solar system, and energy goals.
For a chat about anything and everything solar, Enphase is here to help.
Find out how many batteries your home needs.
Which type of battery is best for storage?
Which type of battery is best for storage depends on your specific needs and circumstances. For home, business, and other property owners, lithium-ion batteries are generally considered the best choice for solar storage today due to their high efficiency, long lifespan, and decreasing costs of adoption.
Compare Enphase solar battery options.
How long do solar batteries hold charge?
How long a solar battery can hold its charge depends on the chemistry of the device. With that said, high-quality solar batteries can typically remain charged for months on end, ready to be discharged when you need it most. In systems designed exclusively for emergency backup solar power, we recommend charging your battery a few times a year to ensure a full charge is retained. all
How many batteries does it take to power a house with solar?
The number of batteries needed to power a house with solar depends on several factors, including your home's energy usage and the size of your system’s components. For the best results, a solar energy professional can provide a detailed assessment to help determine the right number of batteries for your specific needs.
